Biodecolourisation of Reactive Red 120 as a Sole Carbon Source by a Bacterial Consortium—Toxicity Assessment and Statistical Optimisation

Abstract

The application of microorganisms in azo dye remediation has gained significant attention, leading to various published studies reporting different methods for obtaining the best dye decolouriser. This paper investigates and compares the role of methods and media used in obtaining a bacterial consortium capable of decolourising azo dye as the sole carbon source, which is extremely rare to find. It was demonstrated that a prolonged acclimation under low substrate availability successfully isolated a novel consortium capable of utilising Reactive Red 120 dye as a sole carbon source in aerobic conditions. This consortium, known as JR3, consists of Pseudomonas aeruginosa strain MM01, Enterobacter sp. strain MM05 and Serratia marcescens strain MM06. Decolourised metabolites of consortium JR3 showed an improvement in mung bean’s seed germination and shoot and root length. One-factor-at-time optimisation characterisation showed maximal of 82.9% decolourisation at 0.7 g/L ammonium sulphate, pH 8, 35 °C, and RR120 concentrations of 200 ppm. Decolourisation modelling utilising response surface methodology (RSM) successfully improved decolourisation even more. RSM resulted in maximal decolourisation of 92.79% using 0.645 g/L ammonium sulphate, pH 8.29, 34.5 °C and 200 ppm RR120.

Mathematical Modelling of the Growth of Bacillus cereus Strain wwcp1on Malachite Green Dye

“…As previously, the adjusted coefficient of determination (R 2 ), accuracy factor (AF), bias factor (BF), Root-Mean-Square Error (RMSE), and corrected AICc (Akaike Information Criterion) were used to calculate the statistically significant difference between the models [29,[39][40][41][42].…”

Microbial Degradation of Azo Dyes: Approaches and Prospects for a Hazard-Free Conversion by Microorganisms

“…It was also demonstrated that the microbial community comprised of different bacterial classes can partially degrade azo dyes in the absence of an external carbon source [205], while the bacterial consortium comprised of Pseudomonas aeruginosa strain MM01, Enterobacter sp. strain MM05, and Serratia marcescens strain MM06 could use Reactive Red 120 as a sole carbon source [206] The addition of carbon sources can also increase the rate of dye decolorization and degradation. This was shown in a study of Saranraj et al, (2018), wherein the decolorization rate of different azo dyes (Reactive Orange 16, Reactive Black B, and Reactive Yellow MR) increased for various isolates, namely Bacillus odyssey, Bacillus thuringiensis, Bacillus subtilis, Bacillus cereus, Alcaligenes sp., and Nocardiopsis alba, when sucrose was added [207].…”

Green and Facile Synthesis of Porous SiO2@C Adsorbents from Rice Husk: Preparation, Characterization, and Their Application in Removal of Reactive Red 120 in Aqueous Solution

“…Reactive Red 120 (RR120), a type of azo dye (approximately 9.9 million tons used per year) 1 with a complicated organic structure, has been extensively used in the textile industry 2 because the chemical, biological, and photocatalytic stability is very high. Due to these stable and durable properties, the degradation of RR120 by exposure to sunlight, detergents, water, and microorganisms is very difficult.…”